The EAD is also commonly known as “work permit” is issued by the United States Citizenship and Immigration Service (USCIS) to an eligible person to legally work in the U.S. This is not same as the well-known “Green Card”.
In order to obtain an EAD, eligible candidates needs to file Form I-765, Application for Employment Authorization. An EAD is issued to an eligible alien and may work for anyone and anywhere subject to terms such as time limitation stated on the card.
There are over 40 categories that one can obtain an EAD. One category that is somewhat more common is those spouses of holders of E-1, E-2, E-3 and L-1 visas. Also, those who are waiting for Permanent Residence may apply and obtain an EAD. The USCIS also issue replacement cards for lost, stolen or mutilated; and expired cards.
All employers are required by law to ascertain the eligibility of a person to work for them. The U.S. citizens and Green Card holders do not require an EAD to work in the U.S. Also, if you are authorized to work for specific employer, such as a foreign government, you do not require an EAD to work in the U.S.